Clinicians and families generally acknowledge the tremendous impact that high-dose steroid therapy can have on pediatric cancer patients' quality of life, yet only four studies on the psychological/behavioral effects of steroids in pediatric cancer patients have been published in the past 30 years. The objectives of this pilot study are to: a) identify areas of intervention need by assessing the frequency and severity of steroid-related changes in children's behavior, cognition, and disease-related psychosocial adjustment; b) examine how specific risk and resistance variables predict children's behavior and quality of life during steroid administration; c) explore relationships between steroids' effects and adherence. This will be the first theoretically based, prospective, longitudinal, repeated measures study of the psychosocial and neurocognitive effects of steroids. Guided by a stress and resistance framework and previous research, the pre-treatment baseline assessment of predictors could lead to early identification of and intervention with children at risk for adverse responses. It will also be the first study to control for maturation and test sensitivity by including a healthy sibling comparison group. In the early post-diagnosis period before remission induction treatment, children's primary caregivers will complete baseline measures of their own psychological functioning, family functioning, their children's behavior and health-related quality of life; children will complete neuropsychological measures of memory and attention. Assessments will be repeated on day ten of induction and twice during consolidation. Healthy siblings will be assessed at the same time points. Compared to healthy sibling controls, it is expected that children with ALL will experience greater adjustment difficulties during steroid administration. It is also expected that a physician rating of less severe disease status/better prognosis, older child age, male sex, and more positive family functioning will predict more positive psychosocial (behavior and quality of life) outcomes during steroid administration. Repeated measures analyses of variance will be used to test effects of treatment period (baseline, 3 steroid periods) and group status (ALL, healthy sibling) on dependent measures. Multiple regression models will be used to test predictive effects of stress and resistance factors on children's functioning during steroid dosing. Correlations will be used to test relationships between steroid effects and adherence. This study will contribute to the knowledge of steroids' effects and the predictors thereof so that prophylactic interventions to improve quality of life can be advanced.